It is well recognized in the art that the accuracy of delivery of projectiles fired from weapons, particularly rifles and pistols, is at least in a substantial part, a function of the rotational stability (at times referred to as “spin stability” of the projectile in the course of the flight of the projectile from the weapon to a target. This factor is particularly important when employing weapons having rifled barrels, i.e., internally helically-grooved barrels.
In similar manner, it is well known in the art that provision of an open tip in the leading end of an ammunition projectile has a profound effect upon the degree and nature of the structural reaction of the projectile upon it striking an intended target. For example, provision of an open tip (herein referred to as a “meplat cavity”) in the leading end of a projectile is known to increase the degree of structural change of at least the leading end of the projectile when it strikes a target of a given type. Such changes are to a degree preselectable by weakening of the walls of the meplat cavity employing slits or slots which extend partially through the wall thickness of the meplat cavity, shaping the cross-section of the meplat cavity as a rosette or other geometry, etc. All such known techniques for altering the meplat cavity suffer from the problem of uniformity of the structure of the meplat cavity in the course of its formation and/or modifications to the meplat cavity following its initial formation. Such non-uniformity may take many forms or combination of forms, but all of these are subject to disruption of the spin stability of the projectile during its flight from the weapon to the target, or in the very least, lack of uniformity of spin stability from projectile to projectile of any given production lot of projectiles produced. Similarly, such known prior art techniques commonly fail to provide consistency of projectile deformation, even within the same production lot of projectiles.
Additionally, in the known prior art for the manufacture of ammunition projectiles, there exists the problems of inconsistency in the overall length of a given type of projectile occasioned by the mode of development of the meplat cavity of the projectile, including concomitant inconsistency (a) in the overall length of a metal jacketed core type projectile, (b) in the outer diameter and/or the inner diameter of the outward opening of the meplat cavity, and/or (c) in the rate of reduction in the velocity of the projectiles of a given type in the course of their flight from the weapon to a target.
These and other problems associated with the meplat cavities of the prior art projectiles, and the methods employed in the production of such projectiles, ultimately adversely affect the ballistic of the projectiles.